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(No Modek.) 6 sheets-sheen 2. S. C. DAVIDSON. TANGENTIAL IMPULSB TURBINE0R IEELTON WHEEL. No. 584,579.,

Patented June l5, 1897.

me Nunms PETERS co, PHOTD'LITMO.. wAswNoYou. n, c.

(No Model.) 6 Shee't--Sheet'3.l

S. C. DAVIDSON. TANGENTIAL IMPULSB TURBINB 0R PBLTON WHEEL.

510,584,579..` Patented June 15, 1897.

7%@ wwf l Y ffm www j 7a @m www (No Model.) 6 Sheets-Sheet 4.

S.' C. DAVIDSON. TANGENTIAL I MPULSB'TURBINE 0R PELVTo-N WHEEL.V

NQ. 584,579. Patented June 15,- 18917.

(No Model.) Y 6 Sheets-Sheet 5.

s. 0. DAVIDSON. TANGENTIAL IMPULSB TURBINE 0R PBLTON WHEEL. No.584,579."

Patented June 115, 1897.

Ilivrrn rrn'rns SAMUEL CLELAND DAVIDSON, OF BELFAST, IRELAND.

TNGENTIAL IIVIPULSE-TURBINE OR PELTON WHEEL.

SPECIFICATION forming' part of Letters Patent N o. 584,579, dated June15, 1897.

Application nt August 7, 1896.

T0 @ZZ whom, t may concern.-

Be it known that I, SAMUEL CLELAND DA- VIDSON, of Belfast, Ireland, haveinvented certain new and useful Improvements in TangentialImpulse-Turbines or Pelton Wheels, of which the following' is aspecification.

My improvements have reference to the class or type of turbines known astangential impulse or more commonly as Felton wheels, which as hithertoordinarily constructed consist of a number of separatelymade bucketsbolted orotherwise secured upon or around the periphery of a wheel atequal distances apart, and into which buckets jets of the motive fluid(usually water) em ployed for driving same are directed from outside theperiphery of the wheel. Turbine wheels of such construction are notsuitable for driving with steam as the motive fluid, as theirseparately-attached buckets are liable to become bent out of properposition or break away from the wheel, owing to the excessively powerfulcentrifugal force developed by the enormously high velocities at whichsteam-propelled turbines must necessarily revolve when running atefficient working speed. Further, as there are open spaces between thebuckets their advancing sides act like fan-valles on the surroundingatmosphere and cause a loss in their Working efficiency equivalent tothe power absorbed thereby, and the amount of open space that existsbetween the buckets also equivalently diminishes the number that can bemounted on the wheel. Again, the efficiency of impulse-turbines isenhanced by having as many buckets as possible around the peripheryconsistent with the pitch between their dividingvanes, being sufficientto avoid any undue friction in the passage of the motive fluid throughthe buckets, and by having the dividing diaphragms or vanes as thin aspracticable.

The objects, among others, of my invention are to so constructtangential impulse-turbines that they may be driven with one or morejets of steam, vapor, air, or gases, or of water, which may be used atextra high pressures, such as one thousand pounds and npward per squareinch, (hereinafter called the motive iiuid,) without danger of thebuckets breaking away from the wheel or twisting Serial No. 602,006. (Nomodel.)

out of position thereon and without the divisional vanes between thebuckets operating with fan action on the surrounding atmosphere to anyappreciable extent, while a maximum number of buckets may be employedaround the periphery of the wheel in which the dividing-varies areformed of very thin sheet metal.

In constructing my improved impulse-turbines I preferably make thecentral part of the wheel (hereinafter called the turbine wheel) eitheras a disk annulus mounted on arms or spokes of a wheel or between a pairof disks diverging at the center and there riveted to a central hubkeyed on the turbine shaft or as a solid disk similarly mounted on thesaid shaft or spindle, with a flange or rim around the periphery of thesaid disk annulus or solid disk, as the case may be, in which rim thebueketsare formed by a combination of one or more circumferential andsuitablyshaped concave grooves (hereinafter called the rimgrooves 7)formed, preferably, by turning them in the central part of the outerface of said rim with thin sheet-metal vanes or diaphragms (hereinaftercalled the bucketvanes inserted as a firm fit into slits or cuts(hereinafter called cross-cuts) incised across its outer face to thebottom of said rim groove or grooves, whereby same is divided into aseries of buckets; and I preferably set the bucket-vanes at such anangle with the rim of the wheel that when they come opposite any of thejets of motive fluid driving the turbine they are approximately inparallel line therewith, and the cross-section of the concave curve inthe rim-groove is such that the line of junction between it and thebucketvanes inserted across the same` forms axiallydirected semicircularor semielliptical curvatures which constitute the back of the bucketsand around which the path of the motive fluid is directed in passingthrough the buckets. The diameter of this curvature I preferably makeequal to about four to six times the diameter of the jet of motive fluidat the time of its entry thereto, in practice, however, commencing witha minimum diameter of at least half an inch for the smallest sizes ofjets used therewith. The distance apart between the bucket vanesconstitutes the pitch or length of the bucket as measured vroe aroundthe rim, and this length I preferably adjust so that the clear width ofentrance for the jets of motive i'luid between the bucketvanes is equalto about one-half the crosssectional diameter of the motive-fluid jetsat the time of their entry into the buckets, in practice, however,coml'nencingT with a minimum space of at least one-eighth of an inchbetween the bucket-varies for the smallest sizes of jets of motive fluidused therewith. I may also alternatively construct my hereindescribedimproved impulse-turbines with two of said rim-grooves so located sideby side in the rim that when each is turned out to its proper concavecurvature in the outer face of the wheel-rim their curves meet or cutinto one another at their inner edges, whereby a sharp wedge-likeprojection is formedbetweenthem, and which edge is preferably a littlebelow the exposed edge of the bucket-varies when inserted, ashereinbefore described, across the double groove thus formed. The jetsof motive iiuid on being directed upon the said sharp wedge-likedividing` edge between the grooves are split thereby to right and leftinto the axially directed curvatures forming the back of the buckets ineach of the rim-grooves, so that a double-acting bucket is formed bythis combination of double rimgrooves with the bucket-vanes from whichthe return-current of the motive iiuid is discharged outwardly inapproximately equal parts from its opposite ends, and on the marginaledges of the said rim-grooves a sufficient width of the wheel-rim isleft flat for a metal ring to be shrunk on over it, with or without theaddition of a coil of wire wound tightly into a groove around it, so asto bind the bucket-varies and the divided parts of the rim between themsufliciently firmly and strongly togetherto withstand the centrifugalforce developed by the enormously high vclocities at which theseturbines necessarily revolve'when working with steam or highpressurehydraulic jets of about one thousand pounds and upward as motive iiuid.

According to another alternative modification in the construction of thebuckets in my improved impulse-turbines instead of turning out the rimgroove or grooves forming the axially directed back curvatures of thebuckets as a continuous concave groove around the outer face of thewheelrim, whereby the circumferential line of the same is at an acuteangle to the face of the bucket-vanes and an obtuse angle to the backthereof, I form the axiallydirected back curvature of the bucketssubstantially at right angles to the back of each bucket-vane bysubstituting for the said continuous rimgrooves a series of equidistant(and preferably milled-out) semicylindrical-faced steps around thecentral part of the exterior face of the rim, each of which steps is ofa depth equal to about one-half the diameter of the jet of motive iiuidemployed with the same at the time of its entry into the buckets, but inpractice commencing with a minimum of at least one-eighth of an inch forthe smallest jets used therewith. In front of each step there is a flatplane the line of which is at such an angle with the rim of the wheelthat it is approximately parallel with that of the jets of motive fluidwhen opposite the same, so that the said jets may impinge direct intothe upright concave curvature formed by the semicylind rical face ofeach step without any material deiiection thereof by said plane, uponthe face of which a thin sheet -metal vane is closely fitted byinserting it into crosscuts incised across the face of the rim from edgeto edge in corresponding line with said planes and extended sufficientlyback past the 'face of each step for the inserted edge of the vane to bequite covered thereby. I may also alternatively form the back concavecurvatures of each step in pairs located sufiiciently closely togetherthat their inner curves meet in a sharp wedge-like projection, wherebydouble return-buckets are formed between each pair of vanes, similar tothose hereinbefore referred to, and the outer ends of the vanes and thedivided parts of the rim between them are also similarly bound in firmlytogether by shrunk-on metal rings with or without the addition of a coilof wire wound tightly into a groove around it.

In any of the above-described modifications in the construction of thebuckets it will be evident that as there is no interior or side entrancefor the surrounding atmosphere to get into or between the buckets therecan consequently be no free discharge of air therefrom, and the vanesbeing sloped backward from the direction in which the wheel is runninghave a minimum fan action upon any air that may be drawn in as an eddyover the edges of the wheel-rim, and as only a very small volume of aircould get at the vanes by such eddies this form of bucket haspractically no fan action to reduce its efficiency in work. It will alsobe obvious that as the path of the motive iiuid through the buckets isdeiiected around a semicircular or semielliptical curvature itnecessarily returns therefrom in a line practically parallel with and inopposite direction to that of the initial flow of the jet, provided theturbine is held stationary, but when it is working at its most efficientspeed the bucket of course moves away from its position between the timethat the jet iirst enters it and its return therefrom. Consequently theangle of the return-current must necessarily open outward to someextent, so that its return is not altogether parallel with that of itsinitial iiow; but as the thin sheet-metal bucket-varies in any of theforms of construction above described can with facility be eiiicientlyand securely inserted at very short distances apart and as thesemicircular curvature round which the motive fluid passes is also veryshort its return out of the buckets takes place so quickly that thebuckets have not time to move so far IOO IOS

IIO

forward that the angle of the return flow can open outwardly from aparallel line with its initial flow to such an extent as to materiallyreduce its operative efficiency, and as my herein-described improvedturbines may be driven by jets of steam or by extra-high-pressurehydraulic jets delivered from nozzles exterior to their periphery intobuckets formed on the exterior face of their rims by the combination ofconcave grooves or curvatures therein with thin sheet-metal dividingvanes or diaphragms inserted across the same and bound so rigidlytherein that they are capable of withstanding the enormous centrifugalforce developed when they are revolving at efficient Working speed theymay appropriately be termed eXtra-impulse turbines.

It will be obvious that if more power be desired from a given diameterof turbine wheel than can be obtained by multiplying the jets of motivefluid two separate sets of rim-grooves and buckets may be constructed onthe one wheel.

It will also be obvious that when my'inr proved extra-impulse turbinesare required to impart motion in reverse directions, as in the case oftheir employment for driving loeomotives or steamships, two wheels maybe mounted on the one shaft and the vanes inserted therein at oppositeangles to one another andthe motive-fiuid jets arranged to act thereonin opposite directions.

In the accompanying drawings, Figure lis a side elevation, and Fig. 2 across-section on the line ze' of Fig. l, of a turbine constructed Aaccording to one modication of my invention in which two adjoining andintersecting circumferential rim-grooves form, in conjunction with vanesinserted therein, double-acting buckets in circuit around the wheel.Fig. 3 is a longitudinal section on liney y of Figs. 2 and et. Fig. L isa plan. Fig. 5 is a sectional elevation on line x t of Fig. 6, and Fig.o a half cross-section and half elevation, of a turbine constructedaccording to another modification in which two intersecting concavecurves are milled out in the face of each of a successive series ofstepsV around the outer face of the rim-annulus and form the buckets inconjunction with inserted vanes between each step. Fig. 7 is ahalfcross-section of another modification in which there is one singlecircumferential riem-groove forining the buckets and a groove or channelformed in the outer circumference of the two shrunk on metal rings, intowhich coils of wire are wound to give the rings greater tensilestrength.. Fig. 8 is a half crosssection of another modification inwhich there are two independent sets of single circumferentialrim-grooves and sets of buckets, so that with double nozzles twice thepower may be developed on the wheel. Fig. 0 is a half crosssection ofanothermodification in which there are two independent sets of doublecircumferential rim-grooves and sets of buckets for use with doublenozzles.

Referring first to Figs. l to 4, A is the turbine wheel, B the diskannulus, and C C the circumferential grooves therein. D D are the vanesinserted across the grooves C C, thereby forming the buckets. E and Eare the dished plates, and F the hub, of the wheel which is keyed orotherwise secured to the spindle G. I'I I-I are the shrunk-on rings. Iis the nozzle for the jet of motive fluid, and K the supply-pipe forsame. L is the casing of the turbine, with inspection-doors M, fittedwith plate-glass- N is the waste-motive-fluid outlet from the casing. Ois the bed-plate with ball-bearings P Il mounted thereon. R is thedriving-pulley.

In Figs. 5 and 6, A is the turbine wheel, B the disk annulus withmilled-ont concave semicireular-faced steps C C, and D the vanesinserted across same. E and E are the dished plates, and F the hub, ofthe wheel; I-I Il, the shrunk-on rings.

In Figs. 7, 8, and 9, A is the turbine wheel; B, the disk annulus withcircumferential rimgrooves C GD D, the vanes across same forming thebuckets. E and F.l` are the dished plates, and F the hub; of the wheelI-I, the shrunk-on rings. In Fig. '7, G G are the coils of wire woundinto the channel formed in the shrunk-on rings II II.

It is also intended that in the modifications shown in Figs. 7, 8, and 9the back curvatures may, if desired, be alternatively formed accordingto the way represented in Figs. 5 and 6.

In the accompanying drawings, as above described, only one jet-nozzle isillustrated for directing the motive fluid into the buckets of theturbine wheel, and from a point inv the outer casing which is in linewith the plane of revolution of the turbine, but more than one may beapplied in a similar manner, or the jets may be led from amotivefiuid-supplyduct attached to or forming part of the side of theturbine-casing, as may be preferred, and which latter arrangement isshown and described in my specification for the governing of turbines,the application for which is Serial No. 602,007, filed of equal dateherewith.

I-Iaving now described the nature of my invention and illustrated howthe same is carried into effect by the several modificationshereinbefore described, and represented in the accompanying drawings, Ido not, however, limit myself to the particular methods of constructionas therein set forth, and accordingly claim as my inventionl. Intangential impulse-turbines in which the initial fiow of the motivefluid driving the same is directed into thebuckefs from one or morejet-nozzles exterior to the periphery of the turbine wheel, thecombination with the body of the turbine wheel of a flanged rimrevolving therewith an axiallydirected approximately semicircularcircum- IOO IIO

ferential groove in the outer periphery of groove into buckets saidvanes being inserted into transversely-incised slits across the face ofsaid rim to the full depth of said groove at such an angle to theperipheryof the wheel that when said vanes come opposite the jets ofmotive iiuid driving the turbine they are approximately in parallel linetherewith, and a band around said rim compressing and holding togetherthe said vanes and the divided portions of said rim, substantially asand for the purpose set forth.

2. In tangential impulse-turbines in which the initial flow of themotive fluid driving the same is directed into the buckets from one ormore jet-nozzles exterior to the periphery of the turbine wheel and inwhich the turbine wheel has a flanged rim with an axially-directedcircumferential concave groove of approXimately semicircularcross-section in its outer periphery as and for the purpose set forth,the combination with said rim and its said circumferential groove of asecond similar groove in said rim parallel with the firstdescribedgroove and in sufficiently close proximity to it that their curves meetin a sharp edge and form a wedge-like projection between the twogrooves, and thin sheet-metal vanes dividing both of said grooves intobuckets, said vanes being inserted across said grooves into slits cuttransversely across said rim to the full depth of said grooves and at anangle as described whereby when the jets of motive fluid are directedupon the edge between the two grooves said edge divides it between thetwo grooves and it is discharged from the opposite ends of the doublebuckets thereby formed in a line approximately parallel with and inopposite direction to that of its initial iiow, and a band around saidrim compressing and holding together the divided portions of said rimsubstantially as and for the purpose set forth.

3. In tangential impulse-turbines in which the initial flow of themotive fluid driving the same is directed into the buckets from one ormore jet-nozzles exterior to the periphery of the turbine wheel, thecombination with the body of Ithe turbine wheel of a flanged rimrevolving therewith, a successive series of semicylindricalconcave-faced steps around the outer periphery of said rim the concaveface of each step forming a back curvature thereof, and each of whichsteps is at right angles to the line of motive iiuid when opposite thesame, thin sheet-metal vanes inserted into transverse cuts across theface of said rim and dividing the concave-faced steps and therewithconstituting buckets the said vanes coming into approximately parallelline with the jets when opposite the same, whereby the motive fiuid isdeflected around the concave face of each step in its traverse throughthe bucket and is discharged in a line approximately parallel with andin opposite direction to that of its initial flow and a band around saidrim compressing and holding together the divided portions of said rimsubstantially as and for the purpose set forth.

In witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

SAMUEL CLELAND DAVIDSON.

Witnesses: Y

GEORGE GooLD WARD, HUGH TAYLOR COULTER.

